Comparative antimicrobial effectiveness of a substantive (0.12% chlorhexidine) and a nonsubstantive (phenolic) mouthrinse in vivo and in vitro.

Antimicrobial mouthrinses can play an important role in maintaining oral health by killing cariogenic organisms and preventing plaque and gingivitis. The active ingredients are adsorbed by oral tissues and then gradually released into the saliva. In this article, the effectiveness of a substantive chlorhexidine and a nonsubstantive phenolic antimicrobial mouthrinse were tested. When compared, the results indicated that the two types of mouthrinses are equally effective at killing salivary microbes for up to 30 minutes after rinsing. The prescriptive substantive rinse, however, continued its microbicidal effect for a longer duration (up to 5 hours) than the over-the-counter nonsubstantive rinse. The substantive rinse showed pronounced and measurable zones of inhibition around each well in the agar diffusion assay where the nonsubstantive rinse showed no zone around any well at any time. The substantive rinse also showed a superior ability to inhibit the growth of 28 oral microbes, including some putative periodontopathogens, which were assayed.